CHICAGO (AP) — An influential teachers union endorsed state Sen. Kirk Dillard in the Republican primary for Illinois governor on Friday, calling him "a true friend" of public education and promising needed support from thousands of members throughout the state.

The Illinois Education Association endorsement is just the latest in a stepped-up effort by organized labor to influence the outcome of the GOP primary. Earlier this month, several unions bankrolled television, radio and print ads attacking candidate Bruce Rauner, who has taken the most hard-line positions against labor and other special interests and frequently rails against "union bosses."

On Friday, Dillard called the IEA endorsement the biggest in the governor's race so far. He also signaled he sees an opportunity to step out of the pack, telling reporters there's still "an eternity" to go before the March 18 election and his campaign is picking up momentum.

Dillard and Brady have lagged behind in raising money, and have so far been unable to buy television advertising. Rauner — a wealthy businessman from Winnetka — has been saturating the airwaves since last fall, and Rutherford began running TV ads last week. But his campaign has been dogged in recent weeks by accusations made by a former employee who says Rutherford sexually harassed him and forced him to do campaign work on state time. Rutherford has denied the claims, which were included in a federal lawsuit filed Monday.

IEA President Cinda Klickna said Friday the organization hasn't yet decided how much money it will provide Dillard. But she said she has heard from many of the IEA's more than 130,000 members — both Democrats and independent voters — that the 2014 election is so crucial that they plan to pull a Republican ballot in the primary. In the Democratic primary, Gov. Pat Quinn faces a much lesser-known candidate, Tio Hardiman, a former anti-violence activist from the Chicago area.

"We are in every district, every town in this state and our members get out and work in campaigns and I think that's the most crucial," Klickna said.

IEA gave Dillard $250,000 after endorsing him in the 2010 primary, which he lost to Brady. Klickna said Rutherford also sought the organization's endorsement, but she said the IEA recognized Dillard — whose father was a teacher and daughters go to public schools — as a "strong, consistent ally."

Rauner — a strong supporter of non-union charter schools — used the opportunity to criticize Dillard as a "26-year Springfield insider" who has taken cash in the past from public-employee unions, which traditionally support Democrats.

"This endorsement is a clear reminder to Republican primary voters that Kirk Dillard is part of the problem and will not fundamentally shake up Springfield," Rauner spokesman Mike Schrimpf said.

Dillard shot back, accusing Rauner of "demonizing" working people and union members.

"We should not do that," he said. "The Republican party is not some exclusive club for people that wear neck ties."

The IEA's political action committee is among the unions that have teamed with the Democratic Governors Association to run ads against Rauner. The union — which represents teachers and staff outside Chicago — gave $500,000 to the effort, as did the Service Employees International Union. The Illinois Federation of Teachers gave $250,000.

Rauner has said the unions are lining up against him because they see him as the strongest candidate to take on Quinn in November.